Touch panel system and method for using same

Abstract

The touch panel system of the present invention is adapted for use with a rectangular screen for locating an object placed adjacent the face of the screen. The touch panel includes first and second sources of directional beams, first and second movable beam deflectors positioned in spaced relation to one another, and being movable in a scanning pattern for causing the first and second beams each to be deflected in a scanning pattern which sweeps angularly in a predetermined sweep time interval across the face of the rectangular screen. A reflector is positioned around the screen in such a manner as to be in the path of the beams as they are deflected by the first and second deflectors, and being capable of reflecting the beams at an angle of 180° with respect to the angle at which they strike the reflector. First and second scan detectors are used to detect the end of each sweep of the beams. First and second bend detectors are adapted to sense an interruption in the beams in response to the object being placed adjacent the face of the screen. A controller is connected to the scan detector and the bend detector for calculating the angular positions of the beams at the time they are interrupted by the object and for calculating the position of the object on the screen at that time.

What is claimed is: 
     
       1. A touch panel system for use with a rectangular screen having a ace and upper, lower and opposite side edge; said touch panel system being capable of determining the location of an object placed adjacent said face of said screen, said touch panel comprising: first and second sources of directional beams adapted to generate first and second directional beams;   first and second movable beam deflectors positioned in spaced relation to one another and also positioned in the directional path of said first and second beams, respectively;   said first and second beam deflectors each comprising an elongated flexible reed having one end free to vibrate and having a stationary end opposite from said one end, a deflection member being on said one end of said reed for deflecting said beam;   said deflection members of said first and second beam deflector means each being movable during vibration of said one ends of said reeds of said first and second deflector means respectively for causing said first and second beams each to be deflected in a scanning pattern which sweeps angularly in a predetermined sweep time interval across said face of said rectangular screen and which covers substantially the entire area of said screen;   reflector means positioned around said screen in such a manner to be in the path of said first and second beams as they are deflected by said first and second deflector means, said reflector means being capable of reflecting said first and second beams at an angle of 180° with respect to the angle at which said first and second beams strike said reflector means;   first and second scan detector means for detecting the ends of each of said predetermined sweep time intervals of said first and second beams respectively;   first and second bend detector means for receiving said first and second beams respectively after said beams have been reflected from said reflector means, said first and second bend detector means being capable of sensing an interruption in said first and second beams in response to said object being placed adjacent said face of said screen in the path of said first and second beams; and second scan   controller means connected to said first detector means and also connected to said first and second bend detector means for calculating the angular positions of said first and second beams at the time they are interrupted by said object and for calculating the position of said object on said screen when said object interrupts said first and second beams.   
     
     
       2. A touch panel system according to claim 1 wherein said first and second beam deflectors each further comprise vibration inducing means for causing said free end of said reed to vibrate in reciprocating fashion, said vibration inducing means being adapted to cause said reed to vibrate in resonance. 
     
     
       3. A touch panel according to claim 2 wherein said vibration inducing means cause each of said reeds to oscillate at amplitudes of approximately 45° whereby said beams are each deflected in a scanning pattern which sweeps across said entire face of said screen. 
     
     
       4. A touch panel system according to claim 2 wherein said reed comprises an elongated flexible plastic member having opposite flat faces, said vibration inducing means comprising a pair of ceramic members positioned on opposite sides of said flat faces of said plastic member, said ceramic members each having opposite faces covered with a conductive sheet; clamp means pressing said pair of ceramic members into retentive engagement with said plastic member, whereby the application of an electrical alternating voltage across said pair of ceramic members will cause vibration of said plastic member. 
     
     
       5. A touch panel system according to claim 2 wherein said reed comprises an elongated flexible plastic member having opposite flat faces, and opposite ends, said vibration inducing means being attached to one of said opposite ends of said reed and comprising a pair of ceramic members each having opposite sides coated with a conductive film, an elongated conductive member being positioned between said ceramic members, and clamp means pressing said ceramic members toward and into electrical contact with said conductive member, whereby the application of an alternating voltage from said conductive member across each of said ceramic members will cause vibration of said plastic member. 
     
     
       6. A touch panel system according to claim 2 wherein said reed comprises a pair of elongated plastic strips, each of said strips having opposite faces coated with a conductive film, said strips being secured together in face to face relation, whereby the application of an alternating potential difference across the combined thicknesses of said pair of strips causes said reed to vibrate. 
     
     
       7. A touch panel system according to claim 1 wherein said first and second bend detector means each comprise beam conversion means for converting said reflected beams to a continuous electrical signal, said signal having normal amplitude range in response to no interruption of said reflected beam and having a substantially different amplitude range whenever said reflected beam is interrupted by said object. 
     
     
       8. A touch panel system according to claim 7 wherein said first and second bend detector means each comprise an electric filter circuit for filtering out at least a portion of said signal in said normal amplitude range and for permitting said portion of said signal having said different amplitude range to pass therethrough. 
     
     
       9. A touch panel system according to claim 8 wherein said first and second bend detector means each comprise a diode connected to said filter circuit for receiving said signal from said filter circuit and for further removing remaining portions of said signal having said normal amplitude range. 
     
     
       10. A method for determining the position of an object placed adjacent the face of a screen having an upper edge, a lower edge, and opposite side edges, said method comprising: directing first and second directional infrared beams across the face of said screen from first and second spaced apart source locations;   deflecting each of said first and second beams with first and second vibrating reeds respectively in such a manner to cause said first and second beams to pivot angularly about first and second pivot axes and to sweep completely across said screen in a sweeping pattern within a predetermined time interval, each of said reeds comprising a fixed end and vibrating end, said deflection of said first and second beams being accomplished by said vibrating ends of said first and second reeds respectively;   reflecting said sweeping first and second beams with reflection means positioned around said screen so as to cause said beams to be reflected at an angle of 180° with respect to the angle at which they strike said reflector means;   receiving said reflected first and second beams with first and second bend detector means capable of sensing an interruption in said first and second beams in response to said object being placed in the paths of said first and second beams;   sensing an interruption in said first and second beams with said bend detector means;   comparing the time of said sensed interruption with the ends of said time interval of said sweeping pattern so as to determine the angular positions of said first and second beams at the time they are interrupted by said object;   calculating the location of said object with respect to said screen from the angular positions of said first and second beams at the time they are interrupted by said object.   
     
     
       11. A method according to claim 10 comprising using beam conversion means to convert each of said reflected first and second beams to a continuous electrical signal having a normal amplitude range in response to no interruption of said reflected beams and having a substantially different amplitude range whenever said reflected beam is interrupted by said object, using an electric filter circuit for filtering out at least a portion of said signal in said normal amplitude range, and passing said filtered signal through a diode whereby said diode causes improved definition of said portion of said signal having said different amplitude range. 
     
     
       12. A touch panel system for use with a rectangular screen having a face and upper, lower and opposite side edges; said touch panel system being capable of determining the location of an object placed adjacent said face of said screen, said touch panel comprising: first and second sources of directional infrared beams adapted to generate first and second directional infrared beams;   first and second movable beam deflectors positioned in spaced relation to one another and also positioned in the directional path of said first and second infrared beams, respectively;   said first and second beam deflector means each being movable for causing said first and second infrared beams each to be deflected in a scanning pattern which sweeps angularly in a predetermined sweep time interval across said face of said rectangular screen and which covers substantially the entire area of said screen;   reflector means positioned around said screen in such a manner to be in the path of said first and second infrared beams as they are deflected by said first and second deflector means, said reflector means being capable of reflecting said first and second infrared beams at an angle of 180° with respect to the angle at which said first and second beams strike said reflector means;   first and second scan detector means for detecting the ends of each of said predetermined sweep time intervals of said first and second beams respectively;   first and second bend detector means for receiving said first and second beams respectively after said beams have been reflected from said reflector means, said first and second bend detector means being capable of sensing an interruption in said first and second beams in response to said object being placed adjacent said face of said screen in the path of said first and second beams;   controller means connected to said first and second scan detector means and also connected to said first and second bend detector means for calculating the angular positions of said first and second beams at the time they are interrupted by said object and for calculating the position of said object on said screen when said object interrupts said first and second beams;   said first and second bend detector means each comprising beam conversion means for converting said reflected beams to a continuous electrical signal having a normal amplitude range in response to no interruption of said reflected beam and having a substantially different amplitude range whenever said reflected beam is interrupted by said object;   an electric filter circuit for filtering out at least a portion of said signal in said normal amplitude range and for permitting said portion of said signal having said different amplitude range to pass therethrough;   a diode being connected to said filter circuit for receiving said signal from said filter circuit, Thereby said diode causes an improvement in the clarity of definition of said portion of said signal having said different amplitude range.